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ABOUT THE PROJECT |
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In response to the declining lynx population, the state of New York attempted to reintroduce lynx in the late 1980's. Eighty-three lynx were released in the Adirondack mountains. Unfortunately, this reintroduction failed - the population never became self-sustaining. It is not exactly clear why this effort was unsuccessful. Because the released lynx were not closely monitored, the fate of many of the lynx is unknown.
In 1999 the state
of Colorado initiated a second lynx reintroduction effort.
[See the January 2006 issue of National Geographic for more
details.]
It had been 26 years since lynx disappeared from
Colorado, and now they were on their way back. Unlike the
New
York reintroduction,
However, it is not unusual to have low survival and reproduction during the early stages of a reintroduction effort. Consider the situation: an animal is moved from the wild to captivity, anaesthetized for exams, transported thousands of miles, held in pens near “strangers,” and then released in a completely new environment. It’s not a big surprise that reintroduced animals don’t exhibit typical biological patterns. Biologists have proposed several explanations for what might cause this “reintroduction effect,” but very few studies have actually investigated these theories. Part of the difficulty with answering the question “Why does this occur?” is that many reintroduction programs fail to monitor the animals after they are released. The value of the Colorado reintroduction lies not only in its contribution to lynx conservation, but also in its contribution to conservation science. Their post-release monitoring will allow us to develop a better understanding of what contributes to the success or failure of a reintroduction effort.
Understanding the interaction between hormones and behavior is important, because it can have substantial consequences for an individual's Darwinian fitness (survival and reproduction).
For this project, we employ three different methods for studying behavior.
For captive lynx, we rely primarily on keeper evaluations of an individual's behavior. Understanding an animal’s behavior means not only knowing what they do, but how they do it. People who interact with animals on a regular basis assimilate information about an individual’s temperament over time, and thus keeper surveys can be used to reliably assess an animal’s patterns of behavior, or "behavioral type."
We also conducted direct behavioral observations on a subset of the captive lynx in the study. This allowed us to 1) determine how these quantitative assessments of lynx behavior compare to the qualitative assessments provided by the keeper surveys, and 2) monitor responses to three different stimuli: a snowshoe hare distress cry, beaver castor scent, and a mirror. These behavioral tests allow us to assess how different individuals respond to different sensory stimuli.
For reintroduced and wild lynx, we need to take a whole different approach to studying behavior. Since the lynx cannot be observed directly, all information about their behavior comes from indirect observations. All reintroduced lynx and several naturally-occurring lynx are radio-collared, so information about their movement patterns can be obtained via satellite or airplane. Furthermore, in the winter months, biologists track lynx on foot to get more detailed information about lynx behavior. They follow an individual’s tracks through the snow, recording information about the habitat the lynx moves through, where it rests, how successful prey-chases are, what it kills, and with which other lynx it interacts.
HOW DO WE MONITOR HORMONE EXPRESSION?
Steroid hormones pass through the liver and the gut before they are deposited in feces. Therefore, the hormones in feces are actually hormone metabolites, not pure hormones. Fecal hormone metabolites are extracted using a solution of ethanol and water (#1 on figure below). Then the fecal extract, which contains an unknown concentration of hormone metabolites (UH), is added to a micro-titer plate well which is coated with specific antibodies (e.g. testosterone antibodies; #2). A known amount of specially labeled hormone (LH) is also added to the well (#3). The UH from the extract and the LH undergo a competitive binding process with the antibody. The label on the LH causes a color change, and the intensity of the color indicates the amount of hormone metabolites in the feces (#4). If there are very few UH in the fecal extract, then a lot of the LH binds to the antibody and creates a darker color (#4 top). Conversely, if there are a lot of UH in the fecal extract, then only a few LH bind and the color is very light (#4 bottom).
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Website created and maintained by Kerry Fanson. Last updated 08/20/2008. All materials and photographs on this site are copyrighted. |
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Canada
lynx (Lynx canadensis) are the most abundant felid species
inhabiting North America’s boreal forest. However, southern
populations of lynx have declined dramatically in the last century,
and in 2000, they were listed as a threatened species by the US Fish
and Wildlife Service. While lynx historically extended well into
the northern continental US, anthropogenic activities (e.g.
trapping, habitat destruction) and climate change have dramatically
reduced most US populations. 
the
Colorado Division of Wildlife implemented an
intensive post-release monitoring program.
Biologists monitored where the lynx moved, what they
ate, who they interacted with, and causes of mortality.
However, for the first 4 years of the project, they could not find any signs of
successful breeding. There were no kittens.
Critics of the project cited the mortality rate and lack of
reproduction as a sign of failure.
Behavioral endocrinology is the study of how hormones and behavior
interact. Hormones are chemical signals produced by your body,
and they can have a strong influence over your behavior.
Conversely, certain behaviors you adopt can alter the hormones
produced by your body.
There are thousands of
hormones that circulate through an animal’s body in the course of a
day, helping to ensure
that the body continues to function
normally. Steroids are one class of hormones that play a critical
role in physiological processes (just ask athletes how powerful
these hormones can be!). This class includes several hormones that
are important for reproduction (testosterone, estrogen, and
progesterone) and also hormones that help the body respond to stress
(glucocorticoids). While the body “recycles” most hormones, it
disposes of steroid hormones in urine and feces. Fecal hormone
monitoring is rapidly becoming a popular tool for monitoring an
animal’s reproductive status or stress level, especially because it
is non-invasive. 